While it is ideal to prevent burn injuries from ever happening, unexpected circumstances will always exist. Effective burn treatments help to minimize damage and complications while promoting healing and recovery. All burn injuries are potentially dangerous; that's why healthcare professionals check for immediate injury as well as monitor for delayed complications. If a burn injury is severe, it often requires emergency treatment to prevent shock and infection.
Debridement and excision are both methods of cleansing or preparing a burn wound for proper assessment, classification and treatment. Healthcare professionals perform these procedures for two important reasons—to remove damaged tissue and promote healing.
Debridement removes dead tissue and blisters to expose the true depth and severity of a wound. In some burn injuries, dead tissue naturally falls off as part of the healing process. However, in most cases, active debridement is used to remove damaged skin. Debridement is often an extremely painful procedure. Such removal of damaged tissues is necessary, however, for protection from bacteria and other complications. There are four primary methods of debridement, including: (1) Autolytic-allowing the body to naturally rid itself of dead tissue, (2) Enzymatic-using chemical enzymes to free dead tissue, (3) Mechanical-removing dead tissue through the use of hydrotherapy (water), and (4) Surgical-using sharp instruments or lasers for debridement.
Excision is usually an option for burn wounds determined to be deep second degree or full thickness third degree. This process surgically removes dead tissue in order to prepare a wound for a skin graft or other skin replacement procedure. Thin layers of burned skin are removed until living tissue is exposed. The wound is then cleansed and prepared for grafting.
Treatment of severe burns often requires skin grafting. Prior art methods involve taking skin, both the epidermis and dermis, from unburned sites on the body, i.e. donor sites, and grafting that skin onto the burn wound. The grafted skin attaches to the underlying tissue and effectively closes the wound.
A graft “takes” or is successful when new blood vessels and tissue form in the injured area. Sometimes, skin grafts do not take because of complications such as infection (the most common cause of graft failure) or shearing (pressure causing a graft to detach from the skin). While grafting is a proven and effective treatment, it is important to understand that all prior art skin grafts leave some scarring at both the donor and recipient sites.
By using a patient's own skin to cover a burn wound, the risk of tissue rejection is eliminated. However, skin grafts are often a challenge for patients with severe burns across large portions of their body. In these instances there may not be sufficient donor site skin to immediately cover all of the individual's wounds.
Skin flaps are a complex type of skin graft that attach donor skin and underlying tissue by surgically connecting blood supply from the wound to the transferred skin. Skin flaps and other skin replacement methods are sometimes used in situations where standard skin grafts are not possible or where alternative methods are preferred.
Split-thickness skin grafts (STSGs) are grafts that include the epidermal and part of the dermal skin layers. Grafts up to four inches wide and 10-12 inches long can be removed from flat body surfaces such as the abdomen, thigh or back. These grafts are sewn or stapled into place and covered with compression dressings (tightly wrapped elastic bandages) to provide firm contact. Occasionally, graft sites are left open to air.
Split-thickness grafts are generally not used for weight-bearing parts of the body or for areas subject to friction such as hands or feet. Generally, STSGs are applied as intact sheets or, if there is too little donor skin available, meshed and expanded to maximize graft coverage area. Meshing involves cutting tiny holes in the donor skin so it can be stretched to cover more surface area. The advantages of STSGs include less tissue use, an improved chance of graft survival and minimized donor site damage. However, one disadvantage is that STSGs tend to contract more than full-thickness skin grafts.
Full-thickness skin grafts (FTSGS) consist of both the epidermal and complete dermal skin layers. This type of graft is used instead of a split-thickness skin graft when cosmetic outcome is essential and a skin flap is not available. The thicker the FTSG, the less the potential for contraction. Other advantages include increased resistance to trauma over thin grafts and less distortion functionally and cosmetically.
Comparison of Split-Thickness and Full-Thickness Skin GraftsFeatureSTSGFTSGCompositionEpidermis + part ofEpidermis + dermis +the dermisvarious amounts of fatGraft SurvivalGreater chance ofLess chance of graft survivalgraft survivalResistanceLess resistantMore resistantto TraumaCosmeticPoor cosmeticSuperior cosmetic appearance.Appearanceappearance owing toIt is thicker, preventingpoor color andwound contraction or distortion.texture match. Doesnot preventcontraction.When UsedTemporarily orWhen aesthetic outcome ispermanently afteressential (e.g., facial defects).excision of a burninjury when there isadequate bloodsupply.DonorThigh, buttock,Nearby site, with similar colorSite Tissueabdomen, inner oror texture to skin surroundingouter arm, innerthe defect.forearm.DisadvantagesPoor cosmeticGreater risk of graft failure.appearance, greaterDonor site wound requireschance of distortionprolonged healing time andor contraction.has a greater risk ofdistortion and hypertrophicscar formation.
Sometimes, the area requiring reconstruction lacks the blood supply needed to support a skin graft. The tissues used to reconstruct these wounds must carry their own blood supply. Skin flaps, an advanced form of skin grafting, is a complex procedure in which skin, along with underlying fat, blood vessels and sometimes muscle, is moved from a healthy part of the body to the injured site. In skin flaps located adjacent to the wound site, blood supply may remain attached at the donor site. In instances where the skin flap needs to be attached to a wound elsewhere on the body, surgeons will reattach blood vessels in the flap at the new site through microvascular surgery.
Cosmetically, skin flaps generally produce better results than typical skin grafts because they are often taken from the skin surrounding the injury. This provides the graft superior color and texture match.
When performing a skin graft, special care must be taken to prevent the creation of another difficult-to-heal wound or scar at the donor site. Thick split-thickness and full-thickness skin grafts result in deeper donor site wounds which require longer healing time and may result in contraction and hypertrophic scarring.
With deep split-thickness and full-thickness skin grafts, dermal tissue may be permanently lost at the donor site. The dermal layer cannot grow back by itself and most often results in scar formation. Healing time for most split-thickness skin grafts is approximately 10 to 20 days. Most full-thickness skin grafts require a longer 21 to 90 day period. As a result, medium-thickness split grafts are frequently used as a compromise to provide improved graft survival and durability with minimized donor site complications.
What is needed is an apparatus and method to form a nascent skin graft on a wound area by applying a plurality of individual epidermal cells to that wound area. Applicant's invention comprises such an apparatus and method to apply a plurality of individual epidermal cells to a wound area.